This invention relates to a system for inputting information to be set in advance into a digital control circuit means of a camera, which is applicable, for example, to an automatic exposure control means of cameras so as to set in digitalized photographic information.
As for circuit means such as the automatic exposure control circuit means of cameras, complete digitalization of the above-mentioned circuit means has often been proposed, and accordingly, a number of proposals concerning arrangements for inputting information into the digital circuit means are already well known to those skilled in the art.
According to one of the prior art arrangements, the introduction of a decoder is proposed as a means for the above-mentioned input system, wherein a specific binary code is arranged to be output from the decoder in correspondence with the selection of one of a plurality of input terminals of the decoder. However, in such a case, not only must a specifically designed decoder having special functions to accomplish the above-mentioned purpose be provided, but the decoder requires quite a large number of specific input terminals.
Another one of the conventional arrangements for a system for inputting information into the digital circuit means can be found in Japanese Laid Open Patent Application No. 50-90324 (1975). The system includes a camera having an automatic exposure control means including a digital computing circuit, in which various photographic information are digitalized so that the output signal from the circuit mentioned above may introduce a set value of the correct exposure. There is further provided an actuator means having a plurality of contacts which are respectively arranged to be changed-over in response to a manual setting of a shutter speed dial, and a circuit means for setting a shutter speed, which is arranged to apply the respective output signals coded in advance to the corresponding terminals of the digital computing circuit mentioned above depending upon the respective, resultant change-over states of the plurality of contacts mentioned above.
However, the arrangement described above requires quite a complicated switching circuit means and is not arranged to be relatively, compactly constructed, particularly if the absolute number of values of information of even the same kind is to be increased, and when several specific classifications of the information is desired.
Furthermore, according to one of other alternative proposals, a certain binary code is arranged to be input through every contact between a code board including a plurality of portions to be contacted, such as the gray code board, and a plurality of brushes, the number of respective contacts between the above mentioned portion and brush directly corresponding to the bit number. However, even by the arrangement as described above, there still remain some problems in that not only is the specific pattern to be ready for the code board quite complicated, but also the number of respective contacts mentioned above corresponding to the number of bits arranged for the code board mentioned above, as specifically disclosed in U.S. Pat. No. 3,928,858 (1975) are large. Furthermore, more specifically, the arrangement mentioned above has a fatal, specific disadvantage in that the output of the wrong binary code cannot be substantially avoided, if one of the brush and portion contacts prepared in a manner as mentioned above is simply brought into poor contact with each other.
Furthermore, according to a still further proposal disclosed in Japanese Laid Open Patent Application (Tokkaisho) No. 50-337264, there is provided a system for inputting information into a digital control circuit means. As far as the above-mentioned system is concerned, a train of clock pulses is arranged to be input into a counter means through manually pressing a button, so that the output from the counter means is not only utilized as a representation of the photographic informaton, but also is displayed at the same time during the above-mentioned pressing of the button. More specifically, according to the above-mentioned system, a photographer handling the camera equipped with the above-mentioned system has to continuously press the button and simultaneously, to pay attention to the display which varied in a non-continuous manner or a stepwise manner, until the display mentioned above reaches a predetermined value, so that a value corresponding to the value displayed at the instant of the releasing of the button is input into the digital control circuit means as the predetermined photographic information. Therefore, when the photographer happens to be not paying attention, the predetermined value is overlooked, and thereby, the above-mentioned setting actuation must again be repeated. Furthermore, in addition to the above-mentioned defects, it is naturally quite inconvenient for the photographer in that he must keep observing the above-mentioned display in the course of the setting in of the photographic. Moreover, since the speed of display varied in a manner as described in the foregoing can not help being limited within such a degree as to enable the photographer to confirm the respective non-continuous displayed value, it naturally takes a rather long period to set the predetermined photographic information therewith.